Aluminum alloy; rectangular shape, 10.900 in. Lg, 8.525 in. W, 3.140 in. H; cleaned and treated with preservative, ports covered and sealed; four 0.536 in. Diameter mtg holes in rectangular pattern, 9.375 in. C to c distance along the lg, 7.500 in. C to c distance along the w; furnished with 11 port sleeve inserts